Parameter estimation in bandlimited long-code CDMA systems

This paper considers the problem of parameter estimation in multiuser bandlimited long-code DS/CDMA systems. Centralized (i.e., multiuser) and decentralized (i.e., single-user) estimation procedures for the delay, amplitude and phase offset of the users´ CDMA received signals are derived. The proposed estimation procedures may be devised as two-steps ones: indeed, first a composite channel impulse response is estimated and then, such an estimate is further processed in order to obtain the parameter estimates. Closed-form formulas for the Cramer-Rao lower bound (CRLB) are derived, and the performance of the proposed estimators is numerically contrasted to that of the CRLB and of competing alternatives.